Launch Arma with the mod, ACRE will now automatically copy the necessary plugin to your Teamspeak installation. You should be greeted by the following prompt, click ok:

Teamspeak Settings

In TeamSpeak go to Tools > Options > Addons (side tab) > Plugins (upper tab) > and make sure ACRE2 plugin is enabled and TFAR plugin is disabled. You might have to select "Reload" first in the ACRE2 plugin to be able to enable it.

Do not use "Voice Activation Detection while using Push-To-Talk". This option is in your capture device settings under Advanced Options in your Teamspeak Client. If it is checked you won't be able to transmit over the radio.

In-game control settings (Controls > Addons > ACRE2):

Unmap the "Default Radio Key" mapping.

Map your short-range radio key to "Alt Radio 1 Key", your long range to "ALT Radio 2 key"

Map your "Volume" key to your preference.

Delete all the other mappings

Arma3Sync users be advised: By using Arma3Sync, Arma will always run as admin. This means you will also have to run TeamSpeak as admin to avoid issues with ACRE.

since I ran into that issue I'll post it here:
Do not use "Voice Activation Detection while using Push-To-Talk". This option is in your capture device settings under Advanced Options in your Teamspeak Client. If it is checked you won't be able to transmit over the radio.